It appears that an annual license for the Home Edition is the better deal. Too bad this is not made clear on the website -- that there are likely to be multiple upgrades in a given year. Before version 10, upgrades (requiring an upgrade fee) were between a year an 18 months or so, making the difference in price between buying outright and an annual 'rental' much smaller. Personally, I prefer having software that doesn't become non-functional if you don't keep paying a fee. However, aside for the 'classic' Desktop Mathematica, there seems to be a trend towards a subscription model.
Customer service might be able to help. Since this is a new problem -- only with version 10 and beyond, there may be a different policy.
I looked into giving up my Premier service in favor of the home edition when I retired, and I am glad that I did not. Once you get over the hump of buying the initial license (a big hump, and fortunately well in the past for me), the annual Premier service is a bargain.
